Isothermal Sintering Effects on Phase Separation and Grain Growth in Yttria-Stabilized Tetragonal Zirconia Polycrystal
Isothermal Sintering Effects on Phase Separation and Grain Growth in Yttria-Stabilized Tetragonal Zirconia Polycrystal
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DOI：
10.1111/j.1551-2916.2008.02861.x
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发表时间：
2009-02-01
影响因子：
3.9
通讯作者：
Ikuhara, Yuichi
中科院分区：
文献类型：
--
作者：
Matsui, Koji;Yoshida, Hidehiro;Ikuhara, Yuichi
研究了 3 mol% 氧化钇稳定的四方氧化锆多晶 (Y-TZP) 的等温烧结行为，以阐明烧结过程中的相分离和晶粒生长机制。在1300℃烧结2 h的Y-TZP中，Y-TZP晶粒内部的Y3+离子分布几乎是均匀的，但Y3+离子沿晶界偏析，宽度约为10 nm。当保温时间从2小时增加到50小时时，在靠近晶界的晶粒内部明显形成了高Y3+离子浓度的立方相区域，但平均晶粒尺寸几乎没有增加。该结果表明，立方相区域是在没有晶粒长大的情况下形成的，这可以通过晶界偏析诱导相变机制来解释。在1500℃烧结2h的Y-TZP中，立方相区域已经形成，并且立方相区域和平均晶粒尺寸均随着保温时间的增加而增大。这种晶粒生长行为可以通过基于溶质阻力理论导出的三次方生长低点来解释，这表明立方相区域并不能有效地充当钉扎点。
The isothermal sintering behavior in 3 mol% yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) was investigated to clarify phase-separation and grain-growth mechanisms during sintering. In the Y-TZP sintered at 1300 degrees C for 2 h, the Y3+ ion distribution of grain interiors in Y-TZP was nearly homogeneous, but Y3+ ions segregated along grain boundaries within a width of about 10 nm. When the holding time increased from 2 to 50 h, the cubic-phase regions with high Y3+ ion concentrations were clearly formed in the grain interiors adjacent to the grain boundaries, though the average grain size hardly increased. This result shows that the cubic-phase regions were formed without grain growth, which can be explained by the grain-boundary segregation-induced phase transformation mechanism. In the Y-TZP sintered at 1500 degrees C for 2 h, the cubic-phase regions were already formed, and both of the cubic-phase region and average grain size increased with increasing holding time. This grain-growth behavior can be interpreted by the third-power growth low derived based on the solute drag theory, which indicates that the cubic-phase regions do not effectively act as the pinning points.